UC  SOUTHERN  REGIONAL  LIBRARY  FACILITY 


^  !'ftf^^"'* /n^Ty^  UNITED   STATES  OF  AMERICA: 

'  '^^  WAR   DEPARTMENT. 


AA   001  173  608   9 


.4-> 


'/ 


VL^ 


SIGNAL  SERVICE  NOTES  NO.  XX. 


THUNDER-STORMS  OF  MAY,  1884. 


PREPARED  UNDER  THE  DIRECTION  OF 

BRIG.  &  BVT.  MAJ.  GEN'L  W.  B.  HAZEN, 

CHIEF  SIGNAL  OFFICER  OF  THE  ARMY. 


H.  A.  HAZEN, 

.JUNIOR  PROFESSOR,  OFFICE  OF  THE  CHIEF  SIGNAl,  OFFICER. 


BY  AtlTHOKITY  OF  THE  SECRETARY  OK  W  AK. 


WASHINGTON  CITY 

SIGNAL  OFFICE. 

1885. 


UNITED   STATES   OF  AMERICA: 
WAR   DEPARTMENT. 


SIGNAL  SHRYICE  NOTES  NO.  XX. 


THUNDER-STORMS  OF  MAY,  1884. 


PREPARED  rXDKK  THE  DIREOTIOX  OF 

BRIG.  &  BVT.  MAJ.  GE:t7'L  W.  B.  HAZBN, 

C'lriEF  8I(;VAF,  OFFICKH  OF  THE  AR:\rY, 


H.  A.  HAZEN, 

JUNIOR  PROFESSOR,  OFFICE  OF  THE  CHIEF  SIGNAL  OFFICER. 


KY  AUTHORITY  OF  THE  SECRETARY  OF  AVAR. 

LIBRARY  QF  THE 

LICK  OBSERVATORY. 

WASHINGTON  CITY  : 

SIGNAL  OFFICE. 

1885. 


n^OTE 


The  publication  of  this  Signal  Service  Note  is  made  for  the  purpose  of  bringing 
it  to  the  attention  of  the  public.  The  Chief  Signal  Officer  does  not  thereby  neces- 
sarily endorse  the  views  set  forth. 


(2) 


THUNDER-STORMS  OF  MAY,  1884. 


SRLF 


The  subject  of  thunder-storms  has  attracted  much  attention  of  late  and  a  special 
effort  has  been  made  in  many  foreign  countries  to  collect  detailed  observations  of 
them.  By  such  observations  it  is  hoped  to  elucidate  the  causes  underlying  their 
formation,  their  method  of  development  and  their  general  history.  In  this  country 
.general  observations  have  been  made  by  volunteers  under  instructions  from  the 
Smithsonian  Institute  as  far  back  as  1849,  and  by  the  same  with  those  of  the  Signal 
Service  since  1871. 

These  observers  have  necessarily  been  far  apart  and  not  as  uniformly  distributed 
as  would  be  needed  for  a  systematic  study  of  the  phenomenon.  In  January,  1884, 
the  Chief  Signal  Officer  entered  into  correspondence  with  the  Post  Office  Depart- 
ment looking  to  a  more  uniform  distribution  of  thunder-storm  observers  through  the 
co-operation  of  that  department. 

On  March  i,  the  following  card  for  the  detailed  observation  of  such  storms,  with 
the  accompanying  circular  (No.  4)  of  instruction  was  issued  : 


[Form  16-9. 1 

Tiixj]sri3E;R-sa?oRM:s. 

Data  collected  by  co-operation  of  Post  Office  and  War  Departments. 

Til w II Viiiiiitij 

SUttfi Kind  of  time  lined 


Date  (nioixth  and  ilay)..- 


First  liearfl 

Last  hearrl 

Coniiiig  trum... 
Going  towards. 

Began 

Ended 

Ainiuint 


I  Began.. 
■i  Ended. 


r 


t^Aftor...-{ 


Dir.... 
Force 
Dir.... 


[^  Force  i . 


Distant  Lightning. 


4  THUNDER-STORMS   OF   MAY,   1884. 

[ClRCULAU  XO.  4.] 

SIGNAL  OFFICE, 

War  Department, 

Washington,  March  i,  1884. 

It  is  desired  that  during  the  summer  of  1884  a  few  simple  facts  be  collected  re- 
lating to  the  important  subject  of  thunder-storms.  To  this  end  post-offices  and 
other  centres  have  been  selected,  over  a  limited  extent  of  country,  at  distances  of 
about  forty  miles.  Each  station,  it  will  be  readily  seen,  forms  an  important  point  in 
the  network  of  stations,  and  by  a  comparison  of  these  observations  it  is  hoped  that 
valuable  acquisitions  may  be  made  to  our  knowledge  of  these  frequent  accompani- 
ments of  tornadoes.  Each  thunder-storm  should  have  some  note  made  of  it,  in  order 
that  there  may  be  no  gap  in  any  region. 

The  following  instructions  are  given  for  guidance  in  making  observations.  Each 
card  will  have  sufficient  space  for  three  storms.  Give  town,  county,  state,  time 
(whether  "mountain,"  "central,"  "eastern,"  or  some  city),  and  name  of  observer. 

Thunder-storms  twelve  hours  apart  may  be  taken  as  separate  storms. 

Upon  the  occurrence  of  thunder  give  in  the  appropriate  spaces  month  and  day, 
and,  as  near  as  possible,  the  time  of  first  and  and  last  thunder  connected  with  the 
storm.  Frequently  after  a  storm  has  passed  there  will  be  muttering  of  thunder,  but 
care  should  be  taken  to,  as  far  as  may  be,  watch  the  single  storm. 

Give  the  direction  from  which  the  storm  appears  to  be  coming,  as  shown  by 
threatening  sky,  lightning  flashes  or  thunder  peals  Also,  the  direction  towards 
which  it  goes. 

Give  time  of  beginning  and  ending  of  rain,  with  amount,  if  possible. 

If  the  rain  continues  rather  heavy  more  than  two  hours  after  the  loudest  thunder 
has  passed,  it  may  be  marked  "more  than  two  hours." 

The  amount  of  rain  can  be  measured,  with  a  common  rule,  after  it  has  been  caught 
in  a  pail  or  empty  tomato  can  with  vertical  sides. 

All  observations  of  hail,  size  of  stones,  &c.,  are  very  important. 

Give  directions  and  force  of  wind  before  and  after  the  thunder-storm  ;  for  the 
force  adopt  the  scale  of  calm,  light,  moderate,  brisk,  high,  very  high,  hurricane  or 
tornado. 

If  you  have  a  thermometer  give  the  shade  temperature,  or  temperature  on  north 
side  of  house,  a  little  before  the  storm  reaches  the  station  as  well  as  after  it  has 
passed. 

Note,  also,  if  on  any  day  heat-lightning  is  seen,  the  date,  time  of  appearance,  and 
direction. 

If  there  is  not  time  for  a  full  report,  give  date  and  time  of  severest  part  of  thunder- 
storm. Please  do  not  fail  to  make  some  note  of  every  distinct  thunder-storm  that 
passes  over,  or  within  ear-shot  of,  the  station. 

Observations  should  begin  immediately  upon  the  receipt  of  the  cards. 

This  circular  is  issued  with  the  sanction  of  the  Postmaster  General. 

If  you  know  some  one  in  your  immediate   neighborhood  who  takes  an  interest  in 

meteorology  and  would  be  willing  to  report,  you  are   at  liberty  to  hand  these  cards 

to  him. 

W.  B.  HAZEN, 

Brig.  &  Bvt.  Maj.  Gen'' I, 

Chief  Signal  Officer,  U.  S.  A. 

These  were  sent  to  post  offices  forty  miles  apart,  from  the  Atlantic  to  the  102th 
meridian  west  of  Greenwich,  and  from  the  35th  parallel  of  latitude  to  the  northern 
boundary.  In  Indiana,  Illinois,  and  the  circle  of  one  hundred  and  fifty  miles  radius, 
with  Washington  as  its  centre,  stations  have  been  selected  ten  miles  apart. 
These  cards  met  with  favorable  response   in   a   majority  of  cases,  and  all  records  of 


THUNDER  STORMS   OF  MAY,   18S4.  5 

hail-storms  in  May  and  for  thunder-storms  on  May  i8  and  19  have  been  selected  for 
a  special  study.  Reports  of  five  hundred  different  storms  have  been  received. 
From  these  the  following  facts  have  been  gleaned.  Table  I.  exhibits  a  list  of  all 
the  hail-storms  that  have  been  noted. 

Table  I. — Hail-storms  and  their  relation  to  "  LOW.'''' 


Low. 

s 

1S84. 

Station. 

0    . 

'i  1 

5-- 

i 

Size,  &c.,  of  hailstones. 

^ 

5" 

5 

(S 

Dale  and  hour. 

Mil  en. 

Inches. 

I 

April  20,  S  p.  ni 

Concordia,  Mo 

se. 

240 

29.4 

Pigeon's  eggs. 

2 

29.  5  V-  '" 

MonteviJeo,  Minn.. 

e. 

200 

29.6 

Slight. 

3 

-^i'ly    3.  7-10  P  "I- 

rranlclin,  Iiul 

lie. 

900 

30.1 

4 

4,  2  p.  ni  

E.)ckport,  Dak 

e. 

100 

29.6 

Small. 

5 

5,  3..sop.m... 

Troy,  Mo 

s. 

100 

29.6 

Large  as  hen's  eggs. 

0 

b,  8  p.  m 

Davton,  Ohio 

e. 

50 

29.  S 

8-14  inches  deep. 

7 

8,  8  p.  m  

Kothrockville,  I'a.. 

se. 

125 

29.9 

Heavy. 

S 

9,  1.40  p.  m.. 

Lndlow,  Pa 

s. 

120 

29.8 
29.8 

Small. 

9 

10,  7.15  p.m... 

Mooresvillc,  Ind 

se. 

240 

Large  as  peas. 

10 

II,  9.58  ii  m... 

Lyons,  N.  Y 

sw. 

40 

29.6 

Large  as  buckshot. 

11 

1 1 ,  2  p.  in 

Statesville,  N.  0 

* 

* 

29 -75 

.3''  deep. 

12 

ii,  3.15  p.m... 

('owpena,  S.  C 

* 

* 

29-75 

Large  as  partridge  eggs. 

13 
U 

12,  6  p.  m 

16,  1. 10  p.  ni... 

Kt.  Madison,  Iowa.. 
Ogallali,  Kaiis 

0 

100 

29.75 
29.8 

3''  circumterence. 

e. 

15 

17,  5  P-  '" 

Fall  Kiver,  Mass... 

s. 

123 

29.7 

Good  size. 

10 

17,  5P-  1"    -■ 

Providence,  K.  I 

s. 

125 

29.7 

17 

18,  4  a.  m 

Jlurpliysboro,  111... 

8, 

300 

29.7 

Small. 

iS 

18,  2.30  p   m... 

Waverly,  III 

S. 

300 

29.7 

19 

18,  7.30  p.m... 

Worthington,  Ind.. 

se. 

270 

29.7 

20 

19,  12  20  p.  ni.. 

\evav,  Ind 

s. 

300 

29.6 

Size  of  buckshot. 

21 

19,  12.20  p.  m.. 

Westerville,  Ulilo... 

se. 

300 

29-5 

.5"  in  diameter. 

22 

19,  2.10  p.  m... 

Cliepliiie,  Ohio 

se. 

350 

29.6 

23 

19,  6.30  p.m... 

Statesville,  N.  C 

js. 

000 

29.8 

2  + 

19,  7.15  p.  m  . 

Marion,  Va 

.SHo 

29.8 

.5"  in  diameter. 

25 

19,  8.30  p.  111... 

Sandy  Spriu.s;,  Md.. 

se. 

500 

29.8 

20 

20,  8.45  p.  111... 

Sherlock,  Kans 

e. 

50 

29.6 

Light 

27 

21,  12.05  a.  111.. 

(,'lebiirne.  Tex 

se. 

500 

;^9.9 

2S 

21,  3-3°  P-ni  — 

.\llison,  Kans 

e. 

100 

29.6 

29 

21,  8.15  p.  m... 

Maple  Grove,  Ya  .. 

s. 

300 

29  9 

Broke  windows,  &c. 

30 

22,  2.05  p.  111... 

Humboldt,  Iowa  ... 

s. 

50 

29.7 

3t 

22,  4  p   m 

Susse.x,  Wis 

se. 

150 

29  7 

32 
33 

34 

22,  4  p.  m 

25,  I  P-  '" 

20,  noon 

29.7 
30." 
30.0 

Noblesville,  Ind 

e. 

» 

Slight. 

35 

23,  10.20  a.  III. 

llisiug  Sun.  Ind 

e. 

* 

30-0 

3f 

20,  2.40  p.  m... 

Frankfort,  Ind 

e. 

* 

30.0 

Considerable. 

37 

20,  2.40  p.  111... 

StockwcU,  Ind  

e. 

» 

30.0 

3« 

27,  2  p.  m 

Fort  Wayne,  Ind... 

e. 

* 

30.0 

39 

27,  7-10  p.  m... 

Chambersburg,  Pa.. 

ne. 

* 

30-0 

Size  of  peas. 

40 

27,  7.40  p.m... 

Wytheville.  \a.  .  .• 

s. 

*• 

30.0 

41 

29,  4  p.  ni 

Sherlock,  Kans 

ne. 

300 

29.9 

Mean, 

omitting  indetiiiito  . 
of  all 

se. 

238 

29.72 
29.78 

Mean 

1  

1 

*  Not  well  marked. 


f  Atlantic. 


Ten  of  the  falls  occurred  wheri  no  well-defined  LOW  was  present ;  the  remain- 
ing thirty-one  occurred  in  a  direction  southeast  from  LOW  and  at  a  mean  dis- 
tance of  about  two  hundred  and  forty  miles,  with  a  mean  pressure  of  29.72  iiiches. 
These  facts  show  the  prevalence  of  hail-falls  near  LOW,  and  ordinarily  with  a  press- 
ure considerablv  below  the  mean. 


THUNDER-STORMS    OF    MAY    iStH    A.\D    I9TH. 

It  was  found  that  the  16th  ushered  in  a  system  of  thunder-storms  of  great  extent 
and  intensity,  culminating  on  the  i8th  and  19th.  Charts  A  and  B  have  been  pre- 
pared showing  in  full  black  lines  the  progress  of  the  thunder-storm  action  for  each 
four  hours,  beginning  with  4  a.  m.  of  the   iSth  and  with  8  a.  m.  of  the  19th.     There 


6 


THUNDER-STORMS    OF   MAY,    1884. 


is  also  shown  upon  each  map,  l)y  a  dotted  line,  the  position  and  track  of  the  LOW 
accompanying  the  storms.  The  figures  iS-i,  18-2,  18-3,  &c.,  on  this  dotted  line  show 
the  position  of  LOW  at  7  a.  m.,  3  p.  m.,  and  11  p.  m.,  respectively. 

This  LOW  was  central  in  Colorado  on  the  16th,  and  advanced  in  an  east-northeast 
direction  at  a  rate  of  15.3  miles  per  hour,  or  much  less  than  the  average  May 
velocity,  which  has  been  25.7  miles  per  hour  for  the  eight  years  1876-1883.  Table 
II.  shows  the  average  velocity  of  LOW  for  intervals  of  eight  hours  on  the  18th 
and  19th: 

Table  II. 


Interval. 

Velocity 

18-I  to  18-2 

32 

18-2  tu  1S-3 

21 

18-3  to  19-1 

18 

19-1  to  19-2 

27 

19-2  to  19-3 

7 

19-3  to  20-1 

21 

Mean 

21. 0 

The  first  thunder-storms  accompanying  this  LOW  are  reported  from  Kansas 
morning  and  afternoon  of  the  i6th.  No  storms  of  importance  are  reported  on  the 
17th.  On  the  i8th  they  were  general  in  Illinois  and  Indiana.  On  the  19th  the 
region  of  general  action  had  advanced  markedly  to  the  east.  Beginning  with  storms 
in  Indiana  in  the  morning,  we  find  them  spreading  out  like  a  fan  from  this  region  to 
the  southeast  and  east  (see  chart  B).  The  extreme  eastern  limit  of  these  storms  of 
the  19th  was  Mountainville,  New  York,  where  there  was  no  thunder  but  distant 
lightning  was  seen  in  the  southwest.  The  gradual  advance  of  the  storms  from  west 
to  east  and  southeast  is  plainly  indicated  on  maps  A  and  B,  by  following  the  lines 
of  general  action  at  each  four  hours.  The  average  distance  apart  of  these  lines  on 
chart  B  gives  in  Table  III.  the  velocity  of  the  thunder-storm  action  during  each  four 
hour  interval. 

Tahle  III. 


Interval. 

Velocity. 

8  h.  to  noon. 

52 

Noon  to  16  li. 

49 

16  ll.  to  20  ll. 

33 

20  ll.  to  niiilnislit. 

29 

Mean  

41 

This  great  velocity  of  thunder-storms  above  that  of  the  accompanying  LOW, 
amounting  in  this  case  to  more  than  double  on  the  19th,  is  very  interesting  and  de- 
mands further  investigation.  Are  thunder-storms  in  a  measure  entirely  outside  of 
the  influence  governing  low,  or  are  they  at  such  a  great  distance  from  the  LOW  as 
to  attain  a  greater  velocity  going  upon  a  large  circumference  rather  than  upon  a 
straight  line  f  The  rapid  dying  out  of  this  action  in  the  later  hours  of  the  day,  and 
its  starting  up  again  the  next  morning  are  also  noticeable  features. 

On  comparing  the  distances  of  these  storms  we  find  the  average  to  be  about  four 
hundred  and  fifty  miles  from  LOW,  and  the  direction  southeast. 


THUNDER-STORMS    OF   MAY,    1884.  7 

CONCLUSIONS. 

1st.  Hail-falls  occur  ordinarily  with  pressure  much  below  the  normal  to  the  south- 
east of  LOW,  and  at  a  distance  from  it  of  two  hundred  to  three  hundred  miles. 

2d.  Tliunder-storms  advance  from  the  west  toward  the  east  and  southeast,  gen- 
erally accompanying  a  LOW,  and  in  the  southeast  quadrant  at  a  distance  of  four 
hundred  to  five  hundred  miles. 

3d.  The  action  seems  to  die  down  at  night  and  begin  again  in  the  morning,  and 
often  spreads  in  a  fan  shape  to  southeast  and  east. 

4th.  The  velocity  of  the  thunder-storms  is  greater  than  that  of  the  accompanying 
LOW. 

These  preliminary  deductions  are  here  made  simply  as  showing,  what  may  be 
hoped  for  from  a  critical  examination  of  reports  at  stations  near  each  other. 

H.  A.  HAZEN, 

yunior  Professor, 
Office  0/  the  Chief  Signal  Officer. 
June  6,  1884. 


NOTES. 


The  following  notes  are  added  here  in  partial  extension  and  explanation  of  the 
circular  on  page  4: 

The  necessity  of  placing  the  town  or  post  office  address  upon  each  card  will  be 
very  apparent,  many  cards  had  been  received  which  have  lost  much  of  their  value 
because  of  this  omission.  It  is  desired  that  the  post  office  address  be  first  entered 
and  next  the  town,  if  the  two  do  not  coincide,  e.  g.,  Albany  (Menand  Station). 

The  subject  of  the  kind  of  time  used  has  caused  some  confusion.  In  November, 
1883,  most  of  the  railroads  adopted  a  system  of  reckoning  time  which  is  very  con- 
venient and  does  away  with  most  of  the  seventy  or  more  previous  standards.  Four 
standards  are  used,  which  may  be  designated  as  Eastern,  Central,  Mountain,  and 
Pacific.  The  central  meridian  for  each  of  these  is,  for  the  ist,  75^;  2d,  90'^ ;  3d, 
105O,  and  4th,  120°,  all  west  of  Greenwich.  Eastern  time  is  used  by  railroads  and 
most  towns  lying  between  longitudes  67 14°  and  82  i^o  ;  Central  time  is  used  between 
82^0  and  fjlYz^,  &c.  The  simplest  method  of  getting  time  would  be  from  the  near- 
est railroad,  and  in  such  case  the  only  record  needed,  for  "kind  of  time  used," 
is  the  name  of  the  railroad  furnishing  it.  If,  however,  it  is  found  impossible  to 
obtain  railroad  time,  then  the  kind  of  time  used  should  be  noted  thus  :  "  Columbus, 
Ohio,  time,"  "  sundial  time,"  &c. 

It  is  important  that  in  all  cases  the  morning  and  afternoon  records  be  clearly 
distinguished.  The^most  convenient  method  of  doing  this,  and  one  already  adopted 
by  many  observers,  is  'to  divide  the  day  into  twenty-four  hours,  beginning  with 
o  hour,  or  midnight  of  the  previous  day,  and  counting  to  midnight.  By  this  method 
7.15  would  indicate  a  morning  observation  at  7  o'clock  and  15  minutes  ;  23.15  a  night 
abservation  at  11  o'clock  and  15  minutes.  The  morning  hours  would  be  written  as 
at  present,  but  the  afternoon  hours  would  have  twelve  added  to  each.  If  this  system 
is  not  used  care  should  be  taken  to  place  the  needed  a.  m.  or  p.  m.  after  the  figure 
denoting  the  time. 

In  addition  to  the  record  called  for  on  the  card,  it  is  desired,  if  possible,  to  intro- 
duce a  scale  for  thunder-storm  action,  in  order  to  make  future  comparisons  more 
satisfactory.     The  following  scale  is  suggested  : 

1.  Distant  lightning. 

2.  Distant  thunder. 

3.  Moderate  thunder-storm. 


8  THUNDER-STORMS   OF   MAT,   1884. 

4-    Heavy  thunder-storm. 

i;.  Heavy  thunder-storm,  with  very  high  wind,  uprooting  trees,  blowing  down 
buildings,  &c. 

It  is  desired  that  each  card  be  mailed  as  soon  as  filled.  When  there  are  only  two 
cards  left,  make  note  to  that  effect  on  the  card  sent  in. 

It  is  not  necessary  that  an  observer  remain  in  any  one  place  for  all  his  records, 
but  every  thundfer-storm  should  be  recorded  wherever  experienced.  Observers  are 
desired  in  towns  where  there  are  none  now.  Necessary  instructions  and  postal 
cards  will  be  sent  any  person  who  applies  to  the  Chief  Signal  Officer  of  the  Army. 


Form  UH;  F. 


"^lOsi, 


""T^nii.: 


VM  curres  ihow  liaet  of  general  »tsth,  7  ».  m.) ;  18-2  (IStli,  S  p.  m.);  lS-3  (18th,  3  p.  m.),  *c. 


Chart   A— Thunder-storms   May    18,    188-4. 


Fall  curves  show  linei  of  general  act  th,  7  ».  in.) ;  18-2  (ISth,  3  v.  m.) ;  lS-3  (l^ir"SV- m'-T/^^^ 


Chart   B— Thunder-storms    May    19,    1884. 


l«(cio™),I«(lp...).» 


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